There are various methods for machining a traditional light guide plate, e.g., injection molding, dot printing after extrusion molding, dot hot-pressing after extrusion and laser dotting after extrusion. What is common to these methods is that the dots of the formed light guide plate are in an identical plane, i.e., the dots are all distributed on a bottom surface of the light guide plate.
FIG. 1 is a schematic view showing an existing light guide plate. As shown in FIG. 1, the dots of the light guide plate are concave ones. This light guide plate may be formed by injecting, hot-pressing or laser dotting. FIG. 2 is a schematic view showing another existing light guide plate. As shown in FIG. 2, the dots of the light guide plate are convex ones. This light guide plate may be formed by injecting, printing and hot-pressing.
The light guide plate is used to adjust the light by destroying total reflection with dots, and dot density is the most principal factor that will affect the adjustment capacity. The dot density refers to a ratio of an area of the dots to an area of the bottom surface of the light guide plate. In the prior art, because the dots are all distributed on the bottom surface of the light guide plate, there are limitations in the design mode of the dots. The dot density is unlikely to be greater than 100%, and the closer the dot density is to 100%, the harder the machining. In addition, a so-called “dot-connection” phenomenon will easily occur, and the adjustment effect of the light guide plate on the light will be affected. A travel distance of the light will increase along with an increase in the size of the light guide plate. In order to adjust the light at a long travel distance, the dot density is required to exceed the limit of 100%.